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    <title>Document</title>
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    <script>
        // var arr = [1, 2, 3]
        // arr.join()
        // arr.join("_")
        // console.log(arr.join("_"), arr);
        function repeatString(str,n) {
            return new Array(n+1).join(str)
        }
        console.log(repeatString("a",3));
        console.log(repeatString("Hi",5));
        
        
    </script>
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